P Diddy and Bette Midler joined actor Ezra Miller and hip-hop producer Sol Guy in showing their support for the cause

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P Diddy tweeted his support for the tribes' effort to purchase nearly 2,000 acres in the Black Hills of South Dakota.

More celebrities are backing an online campaign to raise money so that Native American tribes in South Dakota can purchase land they consider sacred.

P Diddy and Bette Midler are the latest big names to throw their support behind a fundraising effort to buy nearly 2,000 acres of pristine prairie grass in the Black Hills of South Dakota.

Rock Stars: Then and Now

Three days after the campaign began, P Diddy tweeted: "Help save the Sioux Nation! Click here," and linked to the website. Midler also lent her voice, tweeting: "Incredible story re the Sioux Sacred Grounds. Donate what you can."

More than $18,000 had been raised as of Sunday afternoon — $6,000 flowed in immediately after P Diddy's tweet. The campaign will last through Nov. 30, when the tribes of the Great Sioux Nation must have $9 million in order to purchase the land.

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The tribes have raised $7 million so far for the 1,942 acres, which they call Pe' Sla (pay shlaw), or "old baldy." There are Sioux tribes in the Dakotas, Minnesota, Montana, Nebraska and Canada.

The property is important to their creation story, and tribal members have long held ceremonies there. When the land was put up for sale, tribal members worried it would be developed because of its proximity to Mount Rushmore.

Landowners Leonard and Margaret Reynolds canceled a public auction of the property earlier this year after tribal members expressed outrage. The Reynolds then accepted the tribes' bid to purchase the land for $9 million if they have the money by Nov. 30.

The couple has repeatedly said they will not speak publicly about the land sale.

P Diddy and Midler join actor Ezra Miller and hip-hop producer Sol Guy showing their support for the cause.

Miller, who appears in the recently released movie "The Perks of Being a Wallflower," and Sol Guy flew to South Dakota last month to film a nine-minute documentary-style video about the land that is being used as part of the online campaign.

Miller said the three days he spent in South Dakota learning about the land and the Lakota tribes was life-altering.

"From the moment I arrived to the moment I departed, I was struck repeatedly by an unshakable sensation that this land truly carried something unspeakably important," Miller said in an email interview with The Associated Press. "There is a motion and a beauty out there in those hills that words cannot do justice."

He said the fact that the Lakota tribes have done Sundance ceremonies on the land for thousands of years is a "magical reality," and that America has erased too much of the land's true history.

Sol Guy, whose TV show "4Real" airing on MTV Canada and the National Geographic Channel has taken celebrities such as Cameron Diaz to Peru and Joaquin Phoenix to the Amazon, said he has been busy sharing the information with his various networks to get the word out and is confident the tribes will be successful in raising all the money.

"My first hope is not to demand people to give money," Sol Guy said. "If they can afford it, great. But I think what's more important is that people take it in and learn the history and spread the word and have the conversations about it."

Chase Iron Eyes, a member of the Standing Rock Sioux Tribe who started the online campaign and appeared in the video, said he wants the celebrity endorsements to help raise money, but more than anything, he hopes it will widen the network of people who are thinking about the land and what it means for the tribes.